Amnesty International says it has new evidence Islamic State militants are carrying out "a wave of ethnic cleansing" against minorities in northern Iraq.The human rights group said IS had turned the region into "blood-soaked killing fields".The UN earlier announced it was sending a team to Iraq to investigate "acts of inhumanity on an unimaginable scale".IS and allied Sunni rebels have seized large swathes of Iraq and Syria.Thousands of people have been killed, the majority of them civilians, and more than a million have been forced to flee their homes in recent months.Latest reports say angry relatives of soldiers abducted by IS have forced their way into the parliament building in the capital, Baghdad. Riot police have been trying to bring the situation under control, the Agence France-Presse news agency reports.A member of the Iraqi Shiite militia, Kataib Hezbollah (Hezbollah Brigades), aims his rifle during fighting against Islamic State (IS) fighters, in Amerli town (1 September 2014)Violence in Iraq has escalated dramatically in recent monthsAn Amnesty report released on Tuesday said it had gathered proof that several mass killings took place in the northern region of Sinjar in August.Two of the deadliest took place when IS fighters raided villages and killed hundreds of people on 3 August and 15 August."Groups of men and boys including children as young as 12 from both villages were seized by IS militants, taken away and shot," the UK-based group said."IS is carrying out despicable crimes and has transformed rural areas of Sinjar into blood-soaked killing fields in its brutal campaign to obliterate all trace of non-Arabs and non-Sunni Muslims."